Hi-- You have picked a Great plane to train on. Since it was already built, take 2 things into consideration-- the AUW and motor selection. I have a Kadett Senior that I'm using to train my wife on, and it was built fairly light, at only 5 1/2 lbs, with everything in it, and flies fantastic with an OS 46LA engine. It really doesn't take a lot of power to get a Kadett in the air, and after i removed the 8oz tank, and put a 16 oz in there, I usually have a good 40 min of flight time, and still have some fuel left in the tank when i land. Now, mind you, I am only cruising around with a little less than 1/2 throttle, and it is a dream to fly. The wife is doing well, as she get's the hang of controlling the plane. I am confident of the flight time I have in the air, and have a 2500 MA RX battery in the plane, and a 2500 MA TX battery, so there isn't any issue with battery power. The OS 46 motor really only sips fuel, so it isn't as bad as one may think.
I would weigh ur plane, and really opt for a small 2 stroke, or, a 50-60 size 4 Stroke would be more than enough to fly this plane with authority. I think that the 4 strokes are even more fuel efficient than a 2S.
Do let us know how u plan to complete ur project. Best of luck-- Dean